Duplex pump



K. P. NEILSEN DUPLEX PUMP Filed Feb. 29,' 1936 July 2, 1940.

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July 2, 1940 K. P. NEILSEN 2,206,466

DUPLEX PUMP 4 Sheets-Sheet 2 Filed Feb.' 29, 1936 w VT .W\

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DUPLEX PUMP Filed Feb. 29, 1956 4 Sheets-Sheet 5 July 2, 1940.

K. P. `NEILSEN DUPLEX PUMP Filed Feb. 29, 1936 4 Sheets-Sheet 4 Y /VVE/VTOR. ff/IRL i? NEL/zsm.

Patented July 2, 1940 UNITED STATES PATENT OFFICE 3 Claims.

This invention relates to a novel duplex pump in which a pair of superposed pumping chambers simultaneously take in and discharge on each 'stroke of the pump.

An object of my invention is to provide a novel duplex pump including one traveling piston and one stationary piston, the pumping chambers traversed by each piston being so arranged that fluid is drawn past the stand valve into both of the pumping chambers on the upstroke of the pump, and both of the chambers discharging on the downstroke of the pump.

Another object is to provide a novel bottom discharge valve in a duplex pump of the character stated, the lower pumping chamber discharging thru said bottom discharge valve.

Still another object is to provide a pump of the character stated which will not readily sand up and which will pump a large quantity of liquid 2"'0 on each stroke thereof.

" Other objects, advantages and features of in- 35 of Fig. 6.

Figure 6 is a fragmentary longitudinal sectional View of another type of bottom discharge valve. Figure '7 is a sectional view taken on line 'I-'I of Fig. 6.

Figure 8 is a fragmentary side elevation of the stationary barrel showing the dog clutch.

Figure 9 is a fragmentary longitudinal secu tional view of the upper portion of a modified 5f form of duplex pump. .y

`Figure 10 is a fragmentary longitudinal sectional view of the center portion of the modied pump.U Y Figure 11 is a fragmentary longitudinal sec- 50 tional view of the lower portion of vthe modied pump.

Figure 12 is a-diagrammatic view of the pump shown in Figures 1 to 3. y Figure 13 is a diagrammatic. 55"v shownin Figures `9-to 12.- l

Figure 5 is a sectional view taken on line 5--5y view of the pump Referring more particularly to the drawings, the numeral I indicates the tubing in which my pump is placed and thru which the liquid is carried toI the surface. It is to be noted that in the drawings I have shown the tubing on one side only, to save space.

My pump comprises a top cage 2 which is attached to the lower end of a string of sucker rods-not shown. A ball valve 3 is mounted in J.

the cage 2 for the purpose of controlling'the upper pumping chamber, as will be further described. A sub 4 screws into the cage 2, and the traveling barrel 5 screws onto the sub 4. A reducer 5 screws into the lower end of the traveling barrel barrel 9. The piston 8 is provided with outer packing I0 and inner packing II. ing may be either metallic or non-metallic, as is found most desirable. A pull nut I2 is attached to the upper end 0l' the stationary barrel 9, and the lower extension of the traveling barrel I extends thru this nut. A stationary pull tube I3 extends centrally in the pump and the piston 8 reciprocates over the pull tube. A stationary piston I4 it attached to the upper 'end of the tube I3 and this last named piston is provided with packing I5 which bears against the inside of the traveling barrel 5. This packing I5 also may be either metallic or non-metallic. 'Ihe piston I4 is hollow and the cage I 6 is attached to the upper end of said piston. A ball valve II in the cage I6 controls the movement of fluid thru the piston I4 and into ther upper pumping chamber I8, as will be furthe described.

l Thelower end of the pull tube I3 screws into the fitting I9 and this fitting, in'turn, screws into ay lower discharge valve housing 20. A sub 2I connects the housing 20 and the standing valveV Cage 22.` A` ball valve 23, of usual construction, is positioned within the cage 22. The cage 22 is attached to a spring hold down shoe24 which shoe releasably engages the annular shoulder 25 in the lower end of the tubing I. Thus, it will be evident that the shoe 24', the standing valve cage 22, the bottom discharge valve housing 20, the pull tube I3 and the piston I4 are heldstationary within the traveling barrel 5 and its lower extension 1. i s g LThe traveling piston 8 operates in a lower' pumping chamberZS. vThe `fitting I9 is pro- This packusf,

vided with a plurality of horizontally extending ports 21 which lead from the inside of the fitting into the pumping chamber 26. The lower discharge valve housing 20 is provided with a transverse discharge port 28 which port extends into the annular discharge space 29 in the tubing I. A vertical intake port 30 in the housing 20 is controlled by the ball check 3|. The housing 20 is also provided with by-pass ports 32 which permit the fluid to pass thru the housing and thence upwardly into the lower pumping charnber 26, as will be further described.

The operation of the pump shown in Figs. 1 to 8, inclusive, is as follows:

Assuming that the pump is starting on the upstroke. The sucker rods attached to the cage 2 are pulled upwardly. The ball 3 is seated. A partial vacuum is created in the upper pumping chamber I8 and fluid is drawn past the foot valve 23, thence upwardly in the ports 32, then into the pull tube I3, and finally past the ball check I1 into the upper pumping chamber I8. Atl the same time, the lower pumping chamber 26 is operating to draw uid in also past the foot valve 23, thence thru the ports 32 and 21, thereby filling the lower pumping chamber with uid.

On the downstroke, the ball I1 is seated. The liquid is forced upwardly past the ball check 3 and thence into the tube I. At the same time that liquid is being discharged from the upper pumping chamber, the lower pumping chamber is forcing liquid out thru the ports 21, thence downwardly thru the passages 32, and since the foot valve 23 is seated, the liquid will be forced upwardly, unseating the ball 3I, and the liquid will then pass outwardly thru the horizontal ports 28 into the tubing I and thence to the surface. Part of the liquid may also passupwardly thru the pull tube past the ball I1.

Liquid would find' its way below the stationary piston I4 and to prevent this accumulated liquid from interfering with the operation of the pump, I provide relief holes 33 adjacent therlower end of the traveling barrel 5. Relief holes 34 are provided in the extension of the traveling barrel 1 adjacent the lower end for the purpose of preventing accumulation of sand above the traveling piston 8, and also to relieve the space between the pull tube I3 and the extension of the traveling barrel 9 and the barrel 1. These various holes just described are for the purpose of preventing accumulation of sand in the space between various moving parts and also to relieve these spaces from any accumulation of liquid.

As shown in Fig. 8, I` might providev a dog clutch 36 which will couple the pull nut I2 and the fitting 6, so that the stationary barrel 9 can be held from rotating in order to effectively screw up the rods.

As shown in Fig. Ll, the bottom discharge valve can be inverted from the position shown in Figs. 3 and 6, i. e., the housing 31 is provided with a central upwardly extending tube 38. The ball 39 seats upwardly in the tube 38. The horizontal ports 40 are the same as previously described and perform the same function.

When the ball 39 seats upwardly instead of downwardly-as previously described inY Fig. 6,- the pressure of the fluid inthe tubing will hold the ball 39 seated. When the bottom pumping chamber 26 is discharging, the pressure of the discharged liquid will unseat the ball 39, thus forcing the liquid out thru the ports 4l) and into the tubing I.

In'Figs. 9, 1,0 and ll, -I have disclosed a modified form of duplex pump similar in construction and operation to the pump previously described, with the exception that the bottom discharge valve is eliminated in the modification. The tubing 4I is provided with a coupling 42 which coupling is spaced above the bottom of the well, and the purpose of this coupling will be further described.

A lock fitting 43 is attached to the lower end of the tubing 4I which fitting is engaged by the locking shoe, as will be further described.

My pump includes a top cage 44 to which the lower end of the sucker rods are attached. A ball check 45 is seated in the cage in the usual and well known manner. A traveling barrel 46 is attached to the cage 44 and extends downwardly therefrom. A traveling piston 41 is mounted on the lower end of the barrel 46 and this piston reciprocates in the stationary barrel 48. The stationary barrel screws onto4 a sub 49 and the locking shoe 50 screws into the sub 49 and depends therefrom. The locking shoe engages the fitting 43 for the purpose of holding certain parts of the pump stationary in the tubing.

A standing valve 5I is mounted on the sub 49 for the purpose of controlling the liquid as it enters the pump. The valve 5I is enclosed by a cage 52. A pull tube 53 is attached to the cage 52 and extends upwardly in the pump and thru the traveling piston 41. provided with suitable metallic or non-metallic packing on the inside` against the pull tube 53 and 'on the outside against the stationary barrel 48.

A stationary piston 54 is mounted on the upper end of the pull tube 53. The stationary piston is hollow to permit liquid to move thru it. A cage, 55 is mounted on the upper end of the piston 54 and a ball check 56 in the cage controls l the liquid passing into the upper pumping cham- Starting with the upstroke, the ball 45 isv seated, liquid is drawn past the standing valve 5I,Y thence upwardly thru the pull tube 53., then past'v the vcheek valve 56 and into the upper pumping chamber 51. At the same time, liquid isv drawn past the standing valve 5I thru the cage 52 and into the lower pumping chamber 58.

On the downstroke, the valve 5I is seated, the valve 45 is unseated, the liquid in the chamber 51' is forced out past the valve 5 and into the tubing 4I.v The liquid in the chamber 58 is forced upwardly thru the pull tube 53 and as soon as the pressure of this liquid overcomes the head of liquid in the tubing, the valve 56. will be unseatedy and the liquid will than, pass aronnd the valve 56, thence into the chamber 51,` then past the, valve 45 and into the tubing.

aving described my invention, I claim:

-v l. A duplex pump for wells, a tubing, in which the pump is positioned comprising a standingv The piston 41 is Lio valve, a locking shoe depending from the standing valve, said locking shoe being releasably held in the tubing, a bottom discharge valve housing xedly mounted on the standing valve and arranged above said standing valve, a valve in said housing, said housing having ports opening into the tubing, said valve controlling the flow from Within the pump to said ports, a stationary barrel mounted on the standing valve and rising therefrom, a stationary pull tube mounted on said housing and rising therefrom, a stationary piston mounted on the upper end of the pull tube, a traveling barrel extending over the stationary piston and arranged within the stationary barrel, a traveling piston mounted on the lower end of the traveling barrel, said traveling piston surrounding the pull tube, said pump having a lower pumping chamber below the traveling piston and within the stationary barrel, said -pull tube having ports therein opening into said pumping chamber, a check valve mounted on the upper end of the traveling barrel, and clutch means arranged between the traveling barrel and a stationary barrel, said clutch means bek ing engageable in the lowered position of the traveling barrel, and closure means between the tubing and the stationary barrel, said closure means being arranged below the bottom discharge valve.

2. A duplex pump for wells, a tubing in which the pump is positioned comprising a standing valve, a locking shoe depending from the standing valve, said locking shoe being releasably held in the tubing, a bottom discharge valve housing xedly mounted on the standing valve and arranged above said standing valve, said housing having a transverse port therein opening into the tubing and a vertical port extending into the transverse port, a valve in the vertical port, said f valve controlling the flow from within the pump t'o said ports, a stationary barrel mounted on the standing valve and rising therefrom, a stationary pull tube mounted on the housing and rising therefrom, a stationary piston mounted on the upper end of the pull tube, a traveling barrel extending over the stationary piston and arranged within the stationary barrel, a traveling piston mounted on the lower end of the traveling barrel, said traveling piston surrounding the pull tube, said pump having a lower pumping chamber below the traveling piston and within the stationary barrel, said pull tube having ports therein opening into said pumping chamber and a check valve mounted on the upper end of the traveling barrel and closure means between the tubing and the stationary barrel, and clutch means arranged between the traveling barrel and the stationary barrel, said clutch means being engageable in the lower position of the traveling barrel.

3. A duplex pump for wells, a tubing in which the pump is positionedcomprising a standing valve, a locking shoe depending from the standing valve, said locking shoe being releasably held in the tubing, a bottom discharge valve housing fixedly mounted on the standing valve and arranged above said standing valve, a valve in said housing, said housing having ports opening into the tubing, said valve controlling Ythe flow from within the pump to said ports, a stationary barrel mounted on the standing valve and rising therefrom, a stationary pull tube mounted on said housing and rising therefrom, a stationary piston mounted on the upper end of the pull tube, a traveling barrel extending over the stationary piston and arranged within the stationary barrel, a traveling piston mounted on the lower end of the traveling barrel, said traveling piston surrounding the pull tube, said pump having a lower pumping chamber below the traveling piston and within the stationary barrel, said pull tube having ports therein opening into said pumping chamber, a check valve mounted on the upper end of the traveling barrel, a dog clutch arranged between the traveling barrel and thek stationary barrel, said dog clutch including a female member on one barrel and a male member on the other barrel, said dog clutch being engageable in the lower position of the traveling barrel and closure means between the tubing and the stationary barrel.

KARL P'. NEILSEN. 

